Indescribable atrocities are being committed against innocent civilians in the collapsing Central African Republic where Muslim and Christian fighters have started attacking each other's followers, a top U.N. humanitarian official said Tuesday.

John Ging said the new religious dimension to the conflict in the multiethnic country has instilled "incredible fear" among civilians and "is inciting both communities against each other."

"We are seeing the seeds of a profoundly dangerous development between communities," the director of U.N. humanitarian operations said. "It's a tinderbox that can ignite into something very, very big and very, very bad."

Ging appealed to community and religious leaders to be very careful in what they say to avoid adding to the incitement.

"The situation is fast-moving ... and that's why we want to see (it) ... brought under control very, very quickly rather than let it run out of control which it is at the moment," he said.

One of the world's poorest countries with a long history of chaos and coups, Central African Republic has been in turmoil since a coalition of rebel groups joined forces to overthrow the president in March and put their leader in charge. Since seizing power, the rebels have plunged the country into a state of near-anarchy. They have also been accused by human rights groups of committing scores of atrocities, of widespread looting, killings, rapes and conscription of child soldiers.

Ging, who recently returned from a visit to the beleaguered country, said over half the country's 4.6 million people need humanitarian assistance, including food, water and sanitation.

"The scale of humanitarian suffering is among the worst in the world - and it's getting worse," he said.

Ging said the transitional government has good intentions but doesn't have the means or resources to bring the situation under control "and that's why the international community has to step in in a very large way to help."

"The number one issue today is protection, and the atrocities that are being committed against the civilian population are indescribable," Ging said, citing reports of mutilations, rapes and torture.

On Oct. 10, the U.N. Security Council unanimously backed a new African Union peacekeeping force and demanded swift implementation of a political transition leading to free and fair elections in less than 18 months.

The council said it intends to consider options to support the AU force, which was established in July and has about 1,900 troops.

Central African Republic borders some of the most tumultuous countries on the continent including Congo and Sudan, and some diplomats have expressed concern that even at full strength of 3,600 troops the AU force would not be large enough to deploy beyond key cities to rural areas where there is also great instability.